Adjustable hydraulic operation arrangement

ABSTRACT

A hydraulic arrangement in which a pump is adjustably set to supply pressurized fluid to a number of different hydraulically operated devices with different operating requirements. Each of the devices has connected in front of it a control valve which is, in turn, connected in series with a flow limiter. The control valves have position indicators which transmit signals indicative of the valve position. The flow limiters and the pump are settable through electrical signals derived from an electronic control circuit. The control circuit applies the setting signals to the pump and flow limiters in response to the electrical signals received from the valve position indicators.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority Herbert Busse Stuttgart-Stammheim,Germany 863,21 1

Oct. 2, 1969 May 25, 1971 Robert Bosch GmbH Stuttgart, Germany Oct. 4,1968 Germany ADJUSTABLE HYDRAULIC OPERATION (VSP), (E), 52 (S), 97 (P);91/1 F 10w Limiter Electronic Control Circui! Pump forage Tank 56]References Cited UNITED STATES PATENTS 2,316,926 4/1943 Willett 60/52VSP2,867,091 1/1959 Orloffet al. 60/52VSP Primary ExaminerEdgar W.Geoghegan Att0rneyMichael S. Striker ABSTRACT: A hydraulic arrangementin which a pump is adjustably set to supply pressurized fluid to anumber of different hydraulically operated devices with differentoperating requirements. Each of the devices has connected in front of ita control valve which is, in turn, connected in series with a flowlimiter. The control valves have position indicators which transmitsignals indicative of the valve position. The flow limiters and the pumpare settable through electrical signals derived from an electroniccontrol circuit. The control circuit applies the setting signals to thepump and flow limiters in response to the electrical signals receivedfrom the valve position indicators.

Daub/e -Acting Steering Cylinder Sizer/by wheel limiter l9 Hydraulic ,6Cylinder 5 Hydraulic Maia/- PATENTEDHAY25|97| 3579.987

Double -Acfing Steering Cylinder \Sleering F 10w whiz 25 Aim/gel" F 10w/'7 I [5 imifer Cylinder Elect/uni: Con trol 2 a I 5 HydI'GU/IC MotorLimiter Valve 2 Pump 40 Storage Tank INVENTOR 1 Herbert BU$$ hisATTORNEY ADJUSTABLE HYDRAULIC OPERATION ARRANGEMENT BACKGROUND OF THEINVENTION The present invention resides in a hydraulic arrangement withan adjustable fluid pump which conveys or applies pressurized fluid toat least two hydraulically operated devices. Each one of thehydraulically operated devices is provided with an actuatable controlvalve for applying to the device the required amount of pressurizedfluid obtained from the pump.

Such hydraulic arrangements, heretofore, have had the disadvantage thatthe energy required by the individual hydraulically operated devicescannot always be precisely delivered. Thus, the pump flow is either toolarge, corresponding to the constant pump, or the pressure is too high,corresponding to a regulated pump in a constant pressure system. Both ofthese arrangements lead to energy losses, since the pump delivers morepressurized fluid in one case, and produces a larger pressure in theother case, than what is required by the individual hydraulicallyoperated devices.

Accordingly, it is an object of the present invention to provide ahydraulic arrangement with a plurality of hydraulically operated deviceswhich are driven or operated with particularly high efficiency.

The object of the present invention is achieved by providing anindicator with each control valve which applies to an electronic controlcircuit, an electrical signal representing the position of the controlvalve. A flow limiting valve is, furthermore, provided in front of eachcontrol valve. These flow limiting valves are, in turn, set from signalsdelivered by the electronic control circuit. The electronic controlcircuit, furthermore, provides signals for setting the fluid pump. Thepreceding arrangement of the present invention has the advantage thatthe pump will always deliver only as much fluid as required by thehydraulically operated devices. Asa result of this arrangement of thepresent invention, energy losses are avoided.

Summary of the Invention A hydraulic arrangement by which a pumpdelivers hydraulic fluid to meet the requirements of individuallyhydraulically operated devices connected to a hydraulic line fed by thepump. Each of the hydraulically operated devices is provided with acontrol valve connected directly in front of the device for regulatingthe flow of fluid to the device. Each of the control valves is, in turn,protected by a flow limiter which throttles the fluid to the valve, asrequired. Each of the control valves, furthermore, is provided with avalve position indicator which transmits an electrical signal indicativeof the position or opening of the valve. The pump and the flow limitershave provision by which they may be set through electrical signals. Anelectronic control circuit arrangement receives the electrical signalsfrom the valve position indicators, and after processing these receivedsignals, the electronic control circuit transmits electrical signals tothe pump and the flow limiters for setting and adjusting these devicesso as to result in fluid flow having the requirements of the individualhydraulically operated devices.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING Aschematic diagram of the hydraulicarrangement, in accordance with the present invention, shows theinterrelationship of the hydraulically operated devices, the controlvalves for these devices, the pump which generates pressurized fluid,and the electronic control circuit through which the valves and the pumpare regulated and set so as to result in fluid flow meeting the specificrequirements of the hydraulically operated devices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, anadjustable hydraulic pump 1 is provided with a setting element 2, andclips with its suction in- .let, into a reservoir or storage tank 40.The pump 1 takes the fluid from the storage reservoir 40 and transmitit, under pressure, into the pressure line 3.

A hydraulic line 4 branches from the pressure line 3, and leads tohydraulically operated equipment 5 which, for example, may be in theform of a hydraulic motor used to drive a motor vehicle. The pressurizedfluid in the hydraulic line 4, is applied to the hydraulically operatedequipment 5 through a control valve 6. An adjustable flow limit valve 7is connected in the pressurized line 4, in front of the valve 6. Theflow limit valve 7 is provided with a setting member 8 which isoperatively connected to an electronic control arrangement 10, throughthe control line 9. A control line 11 also interconnects the electroniccontrol arrangement 10 with the setting device 2 for the pump 1. Thecontrol valve 6 is provided with a valve opening or valve positionindicator 12 which is also operatively connected with the controlarrangement 10, by way of the control line 13. The control valve 6possesses two operating positions. In one position of this controlvalve, pressurized fluid flows to the hydraulically operated equipment5, through the hydraulic line 4. In the other one of these twopositions, such flow connection is blocked or cut off.

A hydraulic line 14 further branches from the pressurized line 3, andleads to a second hydraulically operated device,15 which may, forexample, be in the form of a simple hydraulic cylinder on the motorvehicle. Included within this hydraulic line 14 is another control valve16 provided with a valve opening or a valve position indicator 17. Aflow limit valve 18' is connected within this line 14 and in front ofthe control valve 16. A control line 19 interconnects the valve positionindicator 17 with the electronic control circuit 10, whereas acontrolline 21 leads from'the setting device 20 of the flow limitipg valve 18to the electronic control circuit 10. The control valve 16 has twooperating positions. In one of these operating positions, pressurizedfluid flows from the hydraulic line l4'to the hydraulically operatedequipment 15. In the other one of these two operating positions of thevalve 16, the pressurized fluid flows from the hydraulically operatedequipment 15 and into the reservoir or storage tank for the hydraulicfluid.

The pressurized line 3 also leads to a third hydraulically operateddevice 22 which, for example, is in the form of the steering cylinderfor the motor vehicle. Connected to the pressurized line 3, after thehydraulic line branch 14, is a control valve 23 for the hydraulicallyoperated device 22. This control valve 23 is also provided with a valveopening or valve position indicator 24. In this particular case, inwhich this third hydraulically operated device 22 comprises the steeringcylinder for the motor vehicle, the steering wheel is arranged on thevalve position indicator 24.

A control line 25 leads from the valve position indicator 24 to theelectronic control circuit 10. An adjustable flow limiting valve 26 isconnected withinthe pressurized line 3 andbefore the control valve 23.This flow limiting valve 26 is'pr'ovided with a setting device 27 which,in turn, is operatively connected to the control arrangement 10, by wayof the control line 28. The hydraulically operated device 22 is in theform of a double-acting steering cylinder. Fluid flow from the steeringcylinder also leads to a storage tank or reservoir. z

The valve position indicators I2, 17 for the control valves 6, 16,respectively, are, for example, in the form of manually actuatedlinkages. The positions of these valve indicators 12 and 17, as well as24, are transmitted to the electronic control arrangement through theaforementioned control lines.

When any one of the hydraulically operated devices becomes actuated, theelectronic control circuit receives such information from the valveindicator of the valve associated with the particular device which hasbeen actuated. The electronic control circuit responds to thisinfonnation fromthe valve indicator, by causing the pump 1 to beadjusted or set to generating a predetermined fluid pressure andpredetermined fluid flow established by the requirements of thehydraulically operated device. When the respective valve positionindicator is at its maximum opening position, indicating that thecontrol valve is at its maximum opening position, the pump 1 is set sothat it will deliver maximum pressurized fluid flow to the hydraulicallyoperated device. The line pressure which is used depends upon theprevailing fluid resistance of the particular hydraulically operateddevice which is selected. Thus, no energy losses are incurred.

If another hydraulically operated device becomes actuated at the sametime, then the required pressurized fluid flow becomes added to theamount for the first device. Such additional pressurized fluid flowdepends upon the valve position indicator of the associated controlvalve for the hydraulically operated device, as described above. Theline pressure in the fluid conduit is determined by the hydraulicallyoperated device with the greatest resistance. An energy loss appears,thereby, only through pressure difference between two hydraulicallyoperated devices. in this case, the pressurized fluid flow becomesdistributed through the flow limiting valves 12 and 17. These limitingvalves become set through the electronic control arrangement 10,simultaneously with the valve position indicators. The flow limitingvalves serve the purpose of preventing the condition, for example, thatthe entire pressurized fluid flow is first applied to the device withthe lowest fluid resistance, when a plurality of hydraulically operateddevices are actuated simultaneously. The hydraulically operated devicewith lowest fluid resistance is protected through the associated flowregulating valve which throttles the fluid flow to the device in therequired manner.

The addition or summation of the pressurized fluid quantity delivered bythe pump 1 is, of course, also carried out when still furtherhydraulically operated devices are connected to the hydraulic circuit.In the extreme case, the pump is to be designed or selected withcapacity so that all hydraulically operated devices may receive theirmaximum fluid requirements under operating conditions.

The preceding arrangement, in accordance with the present invention, hasalso the advantage that fine control or precise control may be realizedas a result of the treatment or processing of the pressurized flowthrough the valve position indicator at the control valve and thethrottling effect realized from the settable flow-limiting valves. Thisadvantageous feature is accomplished through particularly simpleconstruction of hydraulic control apparatus.

In particular, the electronic control arrangement or circuit 10 includesan adder which adds signals derived from the valve position indicators,and sets the pump 1 responsively so as to provide the required quantityof pressurized fluid. Thus, these valve position indicators 12 and 17may include, for example, electrical potentiometers which transmit theelectrical signals proportional to the position of the respectivevalves. These electrical signals from the different potentiometers onthe valve position indicators are then added in a conventional summingamplifier, for example, for the purpose of obtaining a sum totalrepresenting the full quantity of required fluid flow. The output ofsuch summing amplifier is then applied to the electrically operatedsetting device 2, so that the pump 1 is adjusted to deliver the requiredamount of fluid flow. Such conventional summing amplifiers by which thepump 1 is set, are well known in the art and are, for this reason, notfurther described.

The electronic control arrangement of circuit 10 also includes means fordetecting which ones of the hydraulically operated devices have becomeactuated, so as to apply the required amount of throttling bytheappropriate flow limiters. Such detection of the actuated andhydraulically operated devices, and responsive setting of the flowlimiters. may be accomplished through conventional switching circuits inwhich the appropriate switches corresponding to the devices beingactuated, become set to predetermined positions. The switching circuitwill then in return set the appropriate flow limiters. Such switchingcircuits may be constructed of conventional switching devices such asrelays or transistors, for example. I

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied inhydraulically operated arrangements, it is not intended to be limited tothe details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended.

lclaim:

1. A hydraulic operating arrangement comprising, in combination,adjustable hydraulic pump means; a source of fluid communicating withthe intake of said pump means and being raised in pressure by said pumpmeans; at least two hydraulically operated devices communicating withthe outlet of said pump means and receiving pressurized fluid from saidoutlet; control valve means connected in front of each hydraulicallyoperated device and having variable setting means for controlling theflow of fluid to said device from said pump means; valve positionindicating means arranged with each control valve for transmitting anelectrical signal indicative of the position of said control valve; flowlimit valve means connected in front of each control valve for limitingfluid flow to said control valve and having setting means responsive toan electrical signal so that said limit valve means is set through anelectrical signal applied to said setting means; and electronic controlmeans connected to said valve position indicating means for receivingthe electrical signals from said valve position indicating means and inresponse to said received signals transmitting electrical signals forsetting said limit valve means and adjusting said pump means, wherebysaid pump means delivers pressurized fluid with the requirements of saidhydraulically operated devices.

2. The hydraulic operating arrangement as defined in claim 1 includingpower amplifier means arranged on said pump means and responding toelectrical signals from said electronic control means for setting saidpump means.

3. The hydraulic operating arrangement as defined in claim 1 wherein oneof said hydraulically operated devices comprises a hydraulic motor, saidcontrol valve in front of said hydraulic motor having one position fortransmitting pressurized fluid to said hydraulic motor, and said controlvalve having a second position for inhibiting fluid flow to saidhydraulic motor.

4. The hydraulic operating arrangement as defined in claim I wherein oneof said hydraulically operated devices comprises a hydraulic cylinderand piston, said control valve in front of said hydraluic cylinder andpiston having one operating position for transmitting pressurized fluidto said hydraulic cylinder and having a second operating position fortransmitting fluid from said hydraulic cylinder to said source of fluidcommunicating with the intake of said pump means.

5. The hydraulic operating arrangement as defined in claim 1 wherein oneof said hydraulically operated devices comprises a double-actinghydraulic cylinder and piston for steering a motor vehicle, the steeringwheel of said motor vehicle being mechanically linked to said controlvalve means in front of said double-acting steering cylinder for settingthe control valve in front of said double-acting steering cylinder.

6. The hydraulic operating arrangement as defined in claim 1 whereinsaid flow limit valve means throttle the pressurized fluid flowing tosaid control valve means.

7. The hydraulic operating arrangement as defined in claim 1 whereinsaid hydraulically operated devices have diflerent fluid pressurerequirements for operation.

said main conduit means and leading to said hydraulically operateddevices.

10. The hydraulic operating arrangement as defined in claim 1 includingfluid storage means connected to at least said pump means for storing apredetermined quantity of fluid to operate said hydraulic devices.

1. A hydraulic operating arrangement comprising, in combination,adjustable hydraulic pump means; a source of fluid communicating withthe intake of said pump means and being raised in pressure by said pumpmeans; at least two hydraulically operated devices communicating withthe outlet of said pump means and receiving pressurized fluid from saidoutlet; control valve means connected in front of each hydraulicallyoperated device and having variable setting means for controlling theflow of fluid to said device from said pump means; valve positionindicating means arranged with each control valve for transmitting anelectrical signal indicative of the position of said control valve; flowlimit valve means connected in front of each control valve for limitingfluid flow to said control valve and having setting means responsive toan electrical signal so that said limit valve means is set through anelectrical signal applied to said setting means; and electronic controlmeans connected to said valve position indicating means for receivingthe electrical signals from said valve position indicating means and inresponse to said received signals transmitting electrical signals forsetting said limit valve means and adjusting said pump means, wherebysaid pump means delivers pressurized fluid with the requirements of saidhydraulically operated devices.
 2. The hydraulic Operating arrangementas defined in claim 1 including power amplifier means arranged on saidpump means and responding to electrical signals from said electroniccontrol means for setting said pump means.
 3. The hydraulic operatingarrangement as defined in claim 1 wherein one of said hydraulicallyoperated devices comprises a hydraulic motor, said control valve infront of said hydraulic motor having one position for transmittingpressurized fluid to said hydraulic motor, and said control valve havinga second position for inhibiting fluid flow to said hydraulic motor. 4.The hydraulic operating arrangement as defined in claim 1 wherein one ofsaid hydraulically operated devices comprises a hydraulic cylinder andpiston, said control valve in front of said hydraluic cylinder andpiston having one operating position for transmitting pressurized fluidto said hydraulic cylinder and having a second operating position fortransmitting fluid from said hydraulic cylinder to said source of fluidcommunicating with the intake of said pump means.
 5. The hydraulicoperating arrangement as defined in claim 1 wherein one of saidhydraulically operated devices comprises a double-acting hydrauliccylinder and piston for steering a motor vehicle, the steering wheel ofsaid motor vehicle being mechanically linked to said control valve meansin front of said double-acting steering cylinder for setting the controlvalve in front of said double-acting steering cylinder.
 6. The hydraulicoperating arrangement as defined in claim 1 wherein said flow limitvalve means throttle the pressurized fluid flowing to said control valvemeans.
 7. The hydraulic operating arrangement as defined in claim 1wherein said hydraulically operated devices have different fluidpressure requirements for operation.
 8. The hydraulic operatingarrangement as defined in claim 1 wherein said hydraulically operateddevices have different fluid flow quantity requirements for operation.9. The hydraulic operating arrangement as defined in claim 1 includingmain fluid conduit means connected to the outlet of said pump means forreceiving pressurized fluid from said pump means; and secondary conduitmeans branching from said main conduit means and leading to saidhydraulically operated devices.
 10. The hydraulic operating arrangementas defined in claim 1 including fluid storage means connected to atleast said pump means for storing a predetermined quantity of fluid tooperate said hydraulic devices.